The present disclosure relates generally to the field of optical assemblies. More particularly, the present disclosure is related to systems and methods for optical assemblies (e.g. display assemblies) having one or more adhesive layers.
Conventionally, optical assemblies are utilized in a wide variety of applications including but not limited to applications for displaying, targeting, sensing, etc. Optical assemblies often include a number of layers or components that are coupled together by an adhesive. One exemplary type of optical assembly is a laminated optical assembly.
Optical assemblies include display assemblies, such as laminated display assemblies. Conventional display assemblies often include a display element (e.g., an emissive display element such as an organic light emitting diode (OLED) display element, a liquid crystal display (LCD) element, a plasma element, etc.). The display assembly can also include one or more optical layers and/or optical components. The additional optical layers can be laminated to the display element.
Conventional optical assemblies are often used with a diffuser which can be disposed between a backlight and a display element (e.g., an LCD element). The diffuser more uniformly distributes light through the display element for better image quality. The backlight can be an incandescent backlight, a light emitting diode (LED) backlight, a fluorescent backlight, etc. In one exemplary display application, an avionics display application, the diffuser should generally be compatible with packaging approaches for rugged applications.
Conventional diffusers include surface relief diffusers and plastic bulk diffusers. Plastic surface relief diffusers generally require a substantial backlight cavity depth to achieve a desired uniformity. When utilized with LED backlights, plastic surface relief diffusers may require higher LED counts to achieve a desired uniformity. In addition, plastic surface relief diffusers often require an air interface between the display element (e.g. the LCD) and the diffusion surface and therefore cannot generally be laminated or bonded to the display element. In multi-layer display applications, plastic surface relief diffusers need of an air interface limits the accuracy of alignment between display elements (e.g., no direct bonding to fix relative position between elements) which may result in degraded image quality.
Plastic surface relief diffusers can also be disadvantageous because they reduce transmissiveness efficiency due to reflected light at the air interface and because contact with liquids, such as condensing moisture, can significantly reduce or eliminate light diffusion properties. Plastic surface relief diffusers require skilled handling techniques and attachment to a rigid substrate to be properly mounted in optical cavities. Plastic surface relief diffusers generally add to the cost, weight and production steps associated with the display assembly. Plastic surface relief diffuses are also very sensitive to damage due to incidental contact, and can be easily contaminated.
Conventional plastic bulk diffusers suffer from some of the same drawbacks as plastic surface relief diffusers. Plastic bulk diffusers are incompatible with current liquid bonding and dry film lamination techniques due to poor adhesion. Further, plastic bulk diffusers require one or more combinations of surface modifications (e.g., honing, etc.). Bulk diffusers also require increased backlight cavity depth or higher LED count to achieve desired uniformity. In addition, plastic bulk diffusers add to the cost, weight and production steps (e.g. bonding, bonding perimeters, cleaning, etc.) associated with display assembly.
Therefore, there is a need for an optical assembly which does not require a plastic surface relief diffuser or a bulk diffuser. Further, there is a need for an optical assembly which provides desired uniformity without requiring surface relief diffusers or bulk diffusers. Yet further, there is a need for an optical assembly which can be produced with fewer process steps. Still further, there is a need for a light weight, low cost optical assembly with acceptable diffusion characteristics. Yet further, there is a need for a laminated display assembly that does not require a conventional diffuser. Yet further, there is a need for a lower cost, light weight and rugged display assembly.